JP2000026675A5 - - Google Patents

Description

0007
[Means for solving problems]
In order to solve the above problems, the conductive rubber composition according to claim 1 (hereinafter, also referred to as "rubber composition") is used.
(A) An ethylene-based copolymer rubber composed of ethylene, an α-olefin having 4 to 12 carbon atoms and a non-conjugated polyene, and satisfying the following requirements [1] to [4].
(B) Vulcanizing agent and / or cross-linking agent, and (C) Conductive material,
It is characterized by containing.
[1] The molar ratio (ethylene / α-olefin) of ethylene to α-olefin having 4 to 12 carbon atoms is 5/95 to 80/20.
[2] Iodine value is 5 to 45
[3] Mooney viscosity (ML1 + 4 , 100 ° C.) is 20 to 150.
[4] The glass transition temperature determined by the differential scanning calorimeter is -80 ° C to -50 ° C.

Further, the conductive rubber composition according to claim 2 is the rubber composition according to claim 1, wherein the ethylene-based copolymer rubber (A) further has a [5] branching degree index B of 0.60 to 0. It is characterized by satisfying the requirements of .95.

Then, in the invention of claim 3, in the one according to claim 1 or 2, the α-olefin is 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-. One or two selected from methyl-1-pentene, 1-hexene, 5-methyl-1-hexene, 1-octene, 5-ethyl-1-hexene, 1-nonene, 1-decene, and 1-dodecene. It is characterized by the above.
The invention of claim 4 is characterized in that, in any one of claims 1 to 3, the non-conjugated polyene is a chain polyene having an internal unsaturated bond.
Further, in the invention of claim 5, in the one according to claim 4, the chain polyene having the internal unsaturated bond is 5-ethylidene-2-norbornene, dicyclopentadiene, 5-propyriden-2-norbornene, 5 − Cyclic polyenes such as vinyl-2-norbornene, 2,5-norbornadiene, 1,4-cyclohexadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene; 1,4-hexadiene, 1,6- It is characterized in that it is one or more selected from octadiene, 7-methyl-1,6-octadiene, 5,7-dimethyl-1,6-octadiene, and 1,7-nonadien.
Further, in the invention of claim 6, in the invention according to any one of claims 1 to 5, the non-conjugated polyene is a non-conjugated diene represented by the following structural formula (1) and the following structural formula (2). It is characterized in that it is a combination of α and ω-diene represented by.
CH ₂ = CH- (CR ¹ R ² ) N − CR ³ = CR ^Four -R ^Five (1)
(In the formula, R ¹ ~ R ^Four Indicates the same or different, hydrogen atom or alkyl group having 1 to 8 carbon atoms, and R ^Five Indicates an alkyl group having 1 to 8 carbon atoms, and n is an integer of 2 to 10 carbon atoms. However, R ³ , R ^Four Except when both are hydrogen atoms. )
CH ₂ = CH- (CH ₂ ) M −CH ＝ CH ₂ (2)
(In the formula, m is an integer of 1 to 10.)
The conductive roll according to claim 7 is characterized in that a conductive rubber formed from the conductive rubber composition according to any one of claims 1 to 6 is used as a rubber material.

0011
BEST MODE FOR CARRYING OUT THE INVENTION
The (A) ethylene-based copolymer rubber used in the rubber composition of the present invention is a copolymer composed of ethylene, an α-olefin having 4 to 12 carbon atoms (hereinafter, also referred to as “α-olefin”) and a non-conjugated polyene. It is a polymer.
Examples of the above-mentioned "α-olefin" include 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-hexene, 5-methyl-1-hexene, and the like. Examples thereof include 1-octene, 5-ethyl-1-hexene, 1-nonene, 1-decene, 1-dodecene, etc., preferably 1-hexene and 1-octene are used, and 1-octene is most preferably used. Is. These α-olefins can be used alone or in admixture of two or more.
The molar ratio of ethylene to the α-olefin (ethylene / α-olefin) in the ethylene-based copolymer rubber must be in the range of 5/95 to 80/20 [requirement [1] ], 10 The range is preferably in the range of / 90 to 70/30. If the molar ratio of ethylene is less than 5/95, the rubber composition adheres violently, resulting in a decrease in industrial productivity and workability such as roll processing. On the other hand, if the molar ratio of ethylene exceeds 80/20, the conductive rubber obtained from this rubber composition does not satisfy the characteristics of low hardness and / or low compression set.

Further, the iodine value of the ethylene copolymer rubber (A) needs to be in the range of 5 to 45 [the above requirement [2] ], and is preferably in the range of 20 to 35. If the iodine value is less than 5, the mechanical strength of the obtained conductive rubber is inferior, while if the iodine value exceeds 45, the rubber elasticity is impaired.

Further, (A) the Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the ethylene-based copolymer rubber (hereinafter, also referred to as “Moony viscosity”) must be in the range of 20 to 150 [the above requirements [the above requirements]. 3] ], preferably in the range of 30 to 120.

Further, the glass transition temperature Tg of the (A) ethylene-based copolymer rubber determined by the differential scanning calorimeter (DSC) must be in the range of -80 to -50 ° C [the above requirement [4] ],-. The temperature is preferably in the range of 70 to −58 ° C. If the Tg is less than −80 ° C., the mechanical strength of the obtained conductive rubber is inferior, while if the Tg exceeds −50 ° C., the rubber elasticity is impaired.

Further, as described in claim 2, the branching degree index B of the ethylene-based copolymer rubber (A) is preferably in the range of 0.60 to 0.95 [the above requirement [5] ], 0.70. More preferably, it is in the range of ~ 0.92. If the bifurcation index B is less than 0.60, the rubber elasticity may be impaired and the processing characteristics such as roll processability may be inferior. On the other hand, if the bifurcation index B exceeds 0.95, the mechanical strength of the conductive rubber may be insufficient, and the workability and hardness reduction may not be satisfied.
For the value of this bifurcation index B, refer to the viscosity-GPC method [Michio Kurata, Journal of the Japan Rubber Association, (45) 1972. ], Using the extreme viscosity [η0] of the model copolymer rubber without branching and the viscosity formula [η0] = KMwo (where K is a constant) obtained by the polystyrene-equivalent weight average molecular weight (Mwo). The ultimate viscosity [η1] was calculated from the MWI obtained by GPC measurement of the target copolymer rubber, and then the actual measurement [η2] of the target copolymer rubber was divided by [η1] calculated from the above viscosity formula. I asked for it. Here, [η1] and [η2] are values obtained at 135 ° C. in o-dichlorobenzene, and MW1 is a value obtained at 135 ° C. in o-dichlorobenzene by GPC measurement method.

A vulcanization accelerator can also be used in combination with the above vulcanization agent.
Such vulcanization accelerators include aldehyde ammonia such as hexamethylenetetramine; diphenylguanidine, di (o-tolyl) guanidine, o- tolyl - guanidines such as bi guanides; Chiokarubanirido, di (o-tolyl ) Thioureas such as thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazol, dibenzothiazoledisulfide, 2- (4-morpholinothio) benzothiazole, 2 Thiazols such as-(2,4-dinitrophenyl) -mercaptobenzothiazol, (N, N'-diethylthiocarbamoylthio) benzothiazole; N-t-butyl-2-benzothiazil sulphenamide, Sulfenamides such as N, N'-dicyclohexyl-2-benzothiazil sulphenamide, N, N'-diisopropyl-2-benzothiazil sulphenamide, N-cyclohexyl-2-benzothiazil sulphenamide Thiurams such as tetramethylthioram disulfide, tetraethyl thiuram disulfide, tetra-n-butyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram tetrasulfide; zinc dimethyl thiocarbamate, zinc diethyl thiocarbamate, di-n -Carbamates such as zinc butylthiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, telluryl dimethylthiocarbamate, iron dimethylthiocarbamate; xanthogenates such as zinc butylthioxanthogenate And so on. These vulcanization accelerators can be used alone or in admixture of two or more.
The blending amount of the vulcanization accelerator is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the ethylene copolymer rubber (A).

The conductive rubber obtained from the rubber composition of the present invention is suitably used as a rubber material for various rolls used in printers and copiers by electrophotographic methods, electrostatic recording methods, and the like. That is, a conductive roll using the conductive rubber formed from the conductive rubber composition of the present invention as a rubber material is suitable as the above-mentioned various rolls.

[Α-olefin content (mol%)]
¹³ Measured by C-NMR method. However, the content (mol%) of ethylene and α-olefin in each Example and Comparative Example shows a value when the total amount thereof is 100 mol%.
[Iodine value]
It was measured by infrared absorption spectroscopy.
[Moony Viscosity (ML _{1 + 4} , 100 ° C)]
According to JIS K6300, the measurement was performed under the conditions of a measurement temperature of 100 ° C., preheating for 1 minute, and measurement for 4 minutes.
[Mw / Mn]
Measured by GPC in o-dichlorobenzene at 135 ° C.
[Glass transition temperature (Tg)]
Using a 910 differential scanning calorimeter manufactured by DuPont Instruments (currently TA Instruments), the sample was heated to 180 ° C and then to -90 ° C at a rate of 10 ° C / min. Measured while cooling and raising the temperature at a rate of 20 ° C./min [branching index B]
The sample was measured in o-dichlorobenzene at a sample concentration of 0.15% and 135 ° C. by a 150 CV type GPC manufactured by Waters.

Claims (7)

(A) an ethylene copolymer rubber comprising ethylene, an α-olefin having 4 to 12 carbon atoms, and a non-conjugated polyene and satisfying the following requirements [1] to [4] :
(B) a vulcanizing agent and / or a crosslinking agent, and (C) a conductive material,
A conductive rubber composition comprising:
[1] The molar ratio of ethylene to α-olefin having 4 to 12 carbon atoms (ethylene / α-olefin) is 5/95 to 80/20
[2] Iodine value is 5 to 45
[3] Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 20 to 150
[4] Glass transition temperature determined by differential scanning calorimeter is −80 ° C. to −50 ° C. The conductive rubber composition according to claim 1, wherein the (A) ethylene copolymer rubber further satisfies the requirement [5] .
[5] Branching degree index B is 0.60 to 0.95 The α-olefin is 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 5-methyl-1-hexene, 1-octene, 3. The conductive rubber composition according to claim 1, wherein the conductive rubber composition is one or more selected from 5-ethyl-1-hexene, 1-nonene, 1-decene, and 1-dodecene. object. 4. The conductive rubber composition according to claim 1, wherein the non-conjugated polyene is a chain polyene having an internal unsaturated bond. The chain polyene having an internal unsaturated bond is 5-ethylidene-2-norbornene, dicyclopentadiene, 5-propylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene, 1,4-cyclo Cyclic polyenes such as hexadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene; 1,4-hexadiene, 1,6-octadiene, 7-methyl-1,6-octadiene, 5,7-dimethyl- 5. The conductive rubber composition according to claim 4, wherein the conductive rubber composition is one or more selected from 1,6-octadiene and 1,7-nonadiene.   The non-conjugated polyene is a combination of a non-conjugated diene represented by the following structural formula (1) and an α, ω-diene represented by the following structural formula (2). Item 6. The conductive rubber composition according to any one of Items 1 to 5.
  CH ₂ = CH- (CR ¹ R ² ) n -CR ^Three = CR ^Four -R ^Five       (1)
(Wherein R ¹ ~ R ^Four Are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; ^Five Represents an alkyl group having 1 to 8 carbon atoms, and n is an integer of 2 to 10. However, R ^Three , R ^Four Except when both are hydrogen atoms. )
  CH ₂ = CH- (CH ₂ ) m -CH = CH ₂                   (2)
(In the formula, m is an integer of 1 to 10.) A conductive roll comprising a conductive rubber formed from the conductive rubber composition according to claim 1 as a rubber material.